Resistance-grid.



H. W CHENEY,

' RESISTANCE GRID. APPLIGATION FILED DEG. 28, 1908.

973,000. '0 Patented 0ct. 1s,1910.

25 m an qmx gw I @345 .512

Wow/W3 nrrnn STATES PATENT OFFICE.

HERBERT RT-CHENEY, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO ALLIS-CHALMERSCOMPANY, A CORPORATION OF NEW JERSEY.

RESISTANCE-GRID.

Application filed December 26, 1908.

To all whom 'it may concern:

Be itknown that I, HERBERT W. CHENEY, a citizen of the United States,residing at Milwaukee, in the county of Milwaukee and State ofWisconsin, have invented certain new and useful Improvements inResistance- Grids, of which the following is a full, clear,

and exact specification.

My invention relates to the construction of resistances for use inelectric circuits.

Among the objects of my invention are to obtain strength, durability,compactness, and cheapness of construction.

In addition to providing a resistance possessing superior structuralfeatures, the arrangement of the parts is such that they may all bereadily assembled and firmly held in a permanent or fixed positionexcept those parts intentionally made movable. In this construction,grids are so formed and assembled that one or more of the grids,comprising the resistance, can be taken out and replaced in case ofbreakage or injury without much trouble Conspicuous among the featuresof improvement is the method of reinforcing or stiffening the gridsespecially when they have become excessively heated and renderedflexible.

In the drawings, Figure 1 is a view of one of the grids embodying myinvention; Figs. 9. and 3 are elevations of that shown in Fig. 1; i is aview of a modification of shown in Fig. 1; Fig. 5 is a view of anthermodification of which Fig. 6 is the end elevation.

Resistance grids have been made very heavy and bulky in structure inorder to withstand jars and tendencies to warp out of shape whenexcessively heated. The resistance grids shown in these drawings aremade light in structure. These grids are made of suitable resistancematerial in zigzag form, for example, substantially as shown in Fig. 1,so as to reduce into comparatively small space a resistance ofconsiderable length. The resistance grid consists of conductor 10,formed substantially as shown, and having its elements such as 26 and 27parallel and in integral contact to form a number of end turns such as11 and 23, the conductor terminating in enlarged ends 12 formed of hooks13 or holes open on one side. These hooked ends fit over insulated crossrods or bolts of thesuspending frame. The number of grids may vary acSpecification of Letters Patent.

Patented Oct. 18, 1910.

Serial No. 469,478.

{ cording to the desired length of the suspending frame. The end turnsof the conductors, t such as 11, 14, 15, 16, 17, and 18, are shaped toprovide for the reception of an insulated reinforcing bar 19; forexample'they may be hook-shaped.

Referring to Fig. 3, it is readily apparent how the bar'19 is receivedby the end turns of the conductor, one set, such as 11, 15, and 17,being hooked over in one direction, and the other set, such as 14:, 16,and 18, being hooked over in the opposite direction. The bar 19 is ofsuch dimensions as to cause the pairs of elements, 26 and 27 comprisinga pair, to spring outwardly when the bar is put in place, as shown inFig. 2. The bar is, therefore, tightly clamped. The same reinforcing orstiffening arrangement is used at both ends of the grid. By means ofthis reinforcing it is possible to use grids which are comparativelyfrail in structure without having the elements warp to such an extent,when excessively heated, as'to buckle-111') or come in contact with eachother.

A slight modification of the above arrangement is shown in Figet. Hereonly the extreme end turns 20 and 21 are hookshaped, the other end turnsonly extending up to the top of the insulated reinforcing barbutclamping the same.

In Fig. 5 still another modification is shown. Here the end turns of theconductor, such as 23 and 24, are semi circular in shape to receive areinforcing bar 25 of circular section. Otherwise the arrangement issubstantially the same as that shown in Figs. 1, 2, and 8.

I aim in my claims to cover all modifications which do not involve adeparture from the spirit and scope of my invention.

Vhat I claim as new and desire to secure by Letters Patent is 1. Aresistance grid comprising a conductor having end turns out ofalinement, and an insulated reinforcing bar located between said endturns.

2. I; resistance grid comprising a conductor having end turns out ofalinement, and an insulated reinforcing bar located bebeing on oppositesides of said bar.

3. The combination of a resistance grid comprising a conductor havinghook-shaped end turns, and an insulated reinforcing bait? located insaid. hook-shaped end turns.

tween the end turns, adjacent end turns 4. The combination of aresistance grid comprising a conductor with hook-shaped end turns, andan insulated bar located in said end turns, the elements of said con-'ductor being practically parallel with each other. I

5. The combination of a resistance grid comprising a conductor havinghook-shaped end turns, and an insulated reinforcing bar located in saidend turns, elements of said conductor being sprung when said bar isplaced in said end turns.

6. The combination of a resistance grid comprising a conductor havinghook-shaped end turns, and an insulated reinforcing bar, adjacent onesof said end turns being sprung in opposite directions when said bar isset in place.

7. The combination of a resistance grid comprising a conductor havinghook-shaped end turns, and an insulated reinforcing bar, consecutiveones of said end turns sprung in opposite directions and alternate onesof said end turns in the same direction when said bar is set in place.

8. The combination of a resistance grid comprising a conductor havingend turns, and an insulated reinforcing rod clamped between said endturns, extreme end turns of said conductor being hook-shaped.

9. A zig-zag resistance grid having free end turns, and a single barforming a mutual bracing medium for supporting said end turns.

10. A zigzag resistance grid having end turns, in combination with amember for bracing said end turns to render the grid rigid, end turnsbeing provided with curved projecting portions partially embracing, saidmember to retain the latter in position.

In testimony whereof I aiiix my signature, in the presence of twowitnesses HERBERT W. CHENEY.

Witnesses:

H. C. CASE,

CHAS. L. BYRON.

